Multiphase acrylic modifiers for vinyl halide polymers

ABSTRACT

Vinyl halide polymers characterized by superior mill roll release at high temperatures and resistance to &#39;&#39;&#39;&#39;plate out&#39;&#39;&#39;&#39;, are attained by modifying the polymers with a multiphase acrylic composite polymer comprising (A) a first non-crosslinked phase of molecular weight of up to 450,000 polymerized from a first monomer emulsion or solution of at least 25 weight percent of an alkyl acrylate, wherein said alkyl group has 1 to 18 carbon atoms, 0 to 75 weight percent of another acrylic monomer and 0 to 75 percent of another copolymerizable ethylenically unsaturated monomer, and (B) a final, rigid thermoplastic phase polymerized in the presence of the first phase from an emulsion or solution of about 35 to 100 weight percent of at least one monomer which is a methacrylate, acrylate, styrene or substituted styrene, 0 to 65 weight percent of another acrylic monomer, and 0 to 65 weight percent of another copolymerizable ethylenically unsaturated monomer, wherein the rigid thermoplastic phase has a molecular weight of from about 400,000 to about 5 X 106.

United States Patent Carty et al.

[ Jan. 7, 1975 MULTIPHASE ACRYLIC MODIFIERS FOR VINYL HALIDE POLYMERS[75] Inventors: Daniel T. Carty, Willingboro, N.J.;

James A. Oline, Wyncote, Pa.

. [73] Assignee: Rohm and Haas Company,

- Philadelphia, Pa.

[22] Filed: Dec. 20, 1973 [21] Appl. No.: 426,973 7 Related U.S.Application Data [60] Division of Ser. No. 299,492, Oct. 20, 1972, whichi is a continuation of Ser No. 108,177, Jan. 20, 1971, abandoned, whichis a continuation-in-part of Ser. No 55.979, July 17, 1970, abandoned.

[52] U.S. Cl. 260/885, 260/23 ST, 260/23 AR, 260/23 XA, 260/316, 260/318M, 260/876 R, 260/884, 260/886, 260/899, 260/901 [51] Int. Cl. C08f15/00, C08f 19/00 [58] Field of Search 260/876 R, 885

[56] References Cited UNITED STATES PATENTS 3,041,308 6/1962 Baer260/876 R 3,041,309 6/1962 Baer 260/876 R 3.251.904 5/1966 Souder et al260/876 R 3,488,743 1/1970 Baer et al. 260/879 Primary Examiner-MurrayTillman Assistant ExaminerRichard B. Turer Attorney, Agent, orFirm-Michael B. Fein [5 7] ABSTRACT Vinyl halide polymers characterizedby superior mill roll release at high temperatures and resistance toplate out", are attained by modifying the polymers with a multiphaseacrylic composite polymer comprising (A) a first non-crosslinked phaseof molecular weight of up to 450,000 polymerized from a first monomeremulsion or solution of at least 25 weight percent of an alkyl acrylate,wherein said alkyl group has 1 to 18 carbon atoms, 0 to 75 weightpercent of another acrylic monomer and 0 to 75 percent of an othercopolymerizable ethylenically unsaturated monomer, and (B) a final,rigid thermoplastic phase polymerized in the presence of the first phasefrom an emulsion or solution of about 35 to 100 weight percent of atleast one monomerwhich is a methacrylate, acrylate, styrene orsubstituted styrene, 0 to 65 weight percent of another acrylic monomer,and 0 to 65 weight percent of another copolymerizable ethylenicallyunsaturated monomer, wherein the rigid thermoplastic phase has amolecular weight of from about 400,000 to about 5 X 10 5 Claims, NoDrawings MULTIPHASE ACRYLIC MODIFIERS FOR VINYL HALIDE POLYMERS This isa divisional of Ser. No. 299,492 filed Oct. 20, 1972, which is in turn acontinuation of Ser. No. 108,177 filed Jan. 20, 1971 and now abandoned,which is in turn a continuation-in-part of Ser. No. 55,979 filed July17, 1970, and now abandoned.

Vinyl halide polymers are a class of materials well known in the art,and are widely used for their excellent balance of physical properties,economy, and availability. Included are homopolymers and copolymers ofvinyl halides generally, and particularly the polymers and copolymers ofvinyl chloride. The copolymers contemplated in the art by theexpressionvinyl halide copolymers typically comprise the polymersresulting from the polymerization of a monomer mixture comprising atleast 80%by weight of a polyvinyl halide with up to about by weight ofanother monovinylidene compound copolymerizable therewith, such as vinylacetate, methyl methacrylate, styrene'or the like.

The usefulness of vinyl halide polymers can be increased by physicallyblending various modifiers with the polymers prior to use for plasticobjects. These additives include materials such as lubricants,stabilizers, toners, fillers, pigments, crosslinking agents, tackifiers,plasticizers, processing aids, impact modifiers, and deflectiontemperature under load" improvers. The present invention however isconcerned only with the performance of rigid and plasticized vinylhalide polymers containing resinous modifiers which function asprocessing aids. These modifiers when added to vinyl halide polymersproduce a substantial improvement in the processing behavior of thepolymers particularly in calendering, milling and rolling.

Conventionally, styrene/acrylonitrile copolymers, or

styrene/alkyl methacrylate interpolymers have been used to improve theprocessing characteristics of vinyl halide polymers during operationssuch as milling, calendering or the like, as exemplified by Jennings,U.S. Pat. No. 3,646,417 and Scbwaegerle, U.S. Pat. No. 2,791,600. Inorder to increase production and, in some cases, to produce a product ofparticular desirable propertieswhich are promoted by rapid operation, itis often desirable to conduct milling, calendering or like operations athigher than conventional rates. Such higher rates of operation howeverare accomplished by higher temperatures temperatures at which theconventional aidsbegin to lose their process-lubricating qualities. As aresult, the vinyl halide polymer develops a tendency to adhere toequipment surfaces. It has been found that the modifiers of the presentinvention,

polymer and/or a copolymer of 5 to 95 weight percent alkyl acrylate and95 to 65 weight percent of another alkyl acrylate as a processing aid.U.S. pending applica tion, Ser. No. 31,754 filed 4/24/70, Ryan,describes a PVC modifier which comprises a first cross-linked acrylicelastomer phase and a second acrylic rigid phase. The modifier impartslow die swell characteristics to the PVC. U.S. pending application, Ser.No. 42,882, Whang, shows polymeric modifiers of molecular weights offrom 1,500 to less than 10,000 containing the residue of (A) from topercent by weight alkyl methacrylate and (B) from 0 to 25 percent of atleast one ester of acrylicor methacrylic acid, styrene or substitutedstyrene.

The prior art does not teach the particular composition of the modifiersof the present invention and the superior mill roll release andresistance to plate-out imparted by the modifiers to vinyl halidepolymers. Plateout or roll plating or die-lip deposit has plagued processors from the earliest days of vinyl halide polymer compounding. Thebuild-up of a deposit of incompatible materials on metal processing orfinishing surfaces is more than an annoyance. Changes in product appearance, contamination, and disruption of production due to plate-outcost'money.

Another problem encountered in milling, calendering, extrusion and likeoperations as applied to vinyl halide polymers is the tendency of thepolymer to adhere to processing surfaces at high temperatures. In manyoperations, it is advantageous to operate at high processingtemperatures to increase throughput and to produce a product of certaindesired properties. However, at these processing temperatures, vinylhalide polymers containing conventional modifiers tend to stick oradhere to the surfaces of equipment. The polymers do not readily releasefrom the surfaces and are therefore severely damaged when recovered fromprocessing. The addition ofthe processing aids of the present inventioneffectively prevents these problems. The modified compositions of thepresent invention comprise about 50 to 98 weight percent poly(vinylhalide) and about 2 to 50 weight percent of a multiphase acryliccomposite polymer comprising (A) a first non: crosslinked soft phase ofmolecular weight of up 'to 450,000, preferably 7,500 to 50,000polymerized from a first monomer emulsion or solution of at least 25weight percent of an alkyl acrylate wherein the alkyl group has 1 to 18carbon atoms, 0 to 75 weight percent ofan'other acrylic monomer, and Oto 75 of another copolymerizable ethylenically unsaturated monomer, and

(B) a final, rigid thermoplastic phase polymerized in the presence ofthe elastomer phase from a second monomer emulsion'or solution of about35 to 100 weight percent of at least one monomer which is amethacrylate, acrylate, styrene or substituted styrene,

0 to 65 weight percent of another acrylic monomer, and 0 to 65 weightpercent of another copolymerizable ethylenically unsaturated monomer,wherein the rigid thermoplastic phase has a molecular weight of from400,000 to about 5 X 10 The composite polymer material is ordinarily andpreferably prepared by emulsion or solution polymer ization of the firstphase as a discrete phase from a monomer composition of at least 25weight percent of an alkyl acrylate with an alkyl group of l to 18carbon atoms. Upon completion of the polymerization of the firstphase,'i.e., substantial exhaustion of the monomers in the initialpolymerization composition, the rigid thermoplastic phase is then formedby polymerization in the presence of the first phase, in the sameemulsion or solution, from a monomer mix comprising at leaststantialnumbers of new particles in the emulsion.

The first stage of the polymers of the present invention may bepolymerized from a mixture containing 25 to 95, or preferably 35 to 45weight percent of an alkyl acrylatewherein the alkyl group has 1 to 12carbon atoms. Preferred alkyl acrylates include butyl acrylate, ethylacrylate and 2 ethylhexyl acrylate.

The first or'soft phase may be polymerized from a monomer emulsion orsolution containing to 75 weight percent ofanother acrylic monomer orbetween 35 to 65 weight percent monomer which may be acrylonitrile,methacrylonitrile vinyl acetate, acrylic acid, methacrylic acid,'acrylamide, methacrylamide, N- methylol acrylamide, octyl acrylate,chloroethyl acrylate, alkylthioalkyl acrylates such as ethylthioethylacrylate, and,the-like, alkoxyalkyl's such as methoxyethyl acrylate, andthe like, and alkyl methacrylates wherein the alkylgroup contains 4 to12 carbon atoms and others.

' The monomer emulsionor solution which polymerized to the first phasemay also contain 0 to 75 weight percent, or between 35 to 65 weightpercent of another copolymerizable ethylenically unsaturated monomer.

Such copolymerizablemonomers include styrenes such as styrene,p-chlorostyrene, nitrostyrene, and a-methyl styrene; vinyl toluene;alkyl vinyl ethers; alkyl vinyl ketones; chloroethyl vinyl'ethers, andthe like. In one par.-

' ticular embodiment of the present invention, the vinyl the group.consisting of acrylonitrile, methacrylonitrile, styrene, and substitutedstyrenes. In this embodiment no final, rigid thermoplastic stage isused.

Most preferred soft stages within the scope of the present inventioninclude acrylic interpolymers prepared from monomer mixtures comprisingabout 35 to 100 parts by weight butyl acrylate monomers, about 0 to 65parts by weight otheracrylic monomers, and about 0 to 65 parts by weightof other non-acrylic ethylenically unsaturated monomers. Y

The soft stage of the present invention must have a molecular weight ofup to 450,000. Compositions of molecular weights outside of this rangedo not impart the resistance to plate out and most importantly do notimpart the superior mill r'oll releasecharacteristics to vinyl halidecompositions which are critical features of the compositions of thepresent invention. A preferred molecular weight range for the firstphase of the multiphase acrylic composite interpolymer of this inventionis l0,000 to 50,000. Unless otherwise noted in this specification, theterm molecular weight" refers to viscosity average molecular weight (MThe elasto- 1 novelty resides, not-here alone, but rather in the mannerin which this feature interdependently and cooperatively combines withthe final rigid thermoplastic phase to produce a modifier which impartsto vinyl halide polymers the surprising characteristics of superior millroll release and resistance to plate out. It has also been found thatthe multiphase acrylic composite interpolymers, in addition to impartingmill roll release and resistance to plate-out, additionally may providea polyvinyl chloride system of excellent clarity. Furthermore, thepresent modifiers are easily isolated through spray drying and are quitesuitable for powder blendmg. I

The rigid thermoplastic phase of the composite interpolymer of thepresent invention includes the acrylic thermoplastics polymerized frommonomer mixtures comprising 35 to weight percent of at least one monomerwhich is a methacrylate, acrylate, styrene or substituted styrene, oneor more acrylic comonomers weight of at least one monomer whichis themethacryl- I ate, acrylate, styrene or substituted styrene. Suitablemethacrylates and acrylates include alkyl and aryl esters of methacrylicand acrylic acid wherein the alkyl group may be straight chain, branchedchain, or-cycloalkyl. The cycloalkyl group may be either bridged orunbridged. The term aryl-includes aralkyl and alkaryl groups which maybe substituted, if desired, on both the aliphatic portions and on thearomatic portions. The alkyl acrylates and methacrylates usually includethose wherein the 'alkylgroup contains -1 to 18 carbon atoms and thecycloalkyl acrylates are usually those wherein the cycloalkyl groupcontains 4 to 10 carbon atoms. In thejpreferred alkyl'acrylatesandmethacr lates, the alkyl groups contain 1 to 4 carbon atoms. Ex-

amples of ,alkyland arylmethacrylates andacrylates include methylmethacrylate, ethyl methacrylate, npropyl methacrylate, isopropylmethacrylate, 'n-b utyl methacrylate, isobutyl. methacrylate, stearylmethacrylbly about I to 3 carbon atoms is chain length, but may be othernon-deleterious substituents. Exemplary of the substituted styrenesuseful in the acrylate polymers of the present invention are a-methylstyrene, chlorostyrene, a-hydroxy methyl styrene, and the like.Exemplary substituents for such compounds are halogens,

hydroxy groups, alkoxy groups, as well as lower alkyl groups, etc.

The rigid thermoplastic phase is polymerized from monomermixturescontaining 0 to 65 weight percent or 5 to 15 weight percent of otheracrylic comonomers such as other alkyl and aryl methacrylates'alkyl and'aryl acrylamides, substituted alkyl and aryl acrylic and methacrylicmonomers, where the substituents can be halogen, alkoxy, alkylthio,cyanoalkyl, amino alkylthio,

and other like substituents. The final rigid phase is prepared frommonomer mixtures which also contain to 65 or to weight percent ofanother ethylenically unsaturated monomer which imparts a rigidcharacter to the rigid phase, such as vinyl aromatics, preferablystyrene and a-methylstyrene, vinyl and vinylidene halides, andvinyl-substituted nitriles, vinyl esters, vinyl ethers, vinyl amides,vinyl ketones, olefins, and the like.

The rigid phase is further characterized by molecular weight rangingfrom about 400,000 to5 X 10 preferably 750,000 to 3 X 10 A particularlyeffective molecular weight for attaining the full benefits of thepresent invention is about 750,000 to 1 X 10 which level is alsorelatively'convenient to attain in preparing the composite interpolymersof the present invention.

The modified compositions of the present invention may contain from 75to 99.9 percent by weight of a vinyl halide polymer modified with fromabout 0.1 to

percent by weight of the multiphase acrylic composite interpolymermodifier. Usually, however, and particularly when the modifiedcompositions are used in a milling or calendering operation, the amountof modi fier varies from 1 to about 10 percent by weight, preferablyabout 2 to 4 percent by weight. The modifiers of this invention comprisefrom 50 to 90 percent by weight of the lower alkyl acrylate-containingphase,

from 10 to 50 percent by weight of the final rigid thermoplastic phase.In its preferred composition, the modinvention are prepared by solution,suspension or emulsion polymerization proceduresutilizing a multi-stageor sequential technique. in simplest form, the first phase is formed inan initial stage and the rigid thermoplastic phase is formed in a secondstage. Either the first or rigid phases can thems'eleves also besequentially polymerized. The monomers of the initial stage, togetherwith polymerization initiators, soap or emulsifiers, polymerizationmodifiers and chain transfer agents and the like are formed into theinitial polymerization mix and polymerized, eg by heating and mixing theemulsion,-in well known and wholly conventional fashion, until themonomers are substantially depleted and a seed polymer is formed.Monomers of the second, and in turn, of each additional stage are thenadded with appropriate other materials e.g. supplementary initiators,soap, modifiers, and the like, so that the desired polymerization ofeach stage occurs in sequenceto substantial exhaustion of the monomers.In each stage subsequent to the first, the amounts of the initiatorandsoap, if any, are maintained at a level such that polymerizationoccurs at or near the surface of the existing particles, and nosubstantial number of new particles, or seeds, form in the emulsion.When the phases of the composite interpolymer are either themselvesformed by sequential polymerization, the monomer constituents of thevarious stages of each phase may vary from stage to stage, or all thecomponents can be present throughout the entire phase polymerization.

The stages can vary in hardness, from a very soft elastomer first stageseed to the hardest rigid thermoplastic. Both the elastomer and therigid thermoplastic can contain chain transfer agents, in one or allstages, and, if desired the rigid thermoplastic stagecancontainpolyfunctional crosslinking monomers. However, it is a characteristic ofthe present invention that the first soft stage is non-crosslinked. Whatis meant by the term non-crosslinked" is that no cross linking monomersare present in the elastomer stage.

As already described, and as will be shown in the examples infra controlof the molecular weight of the first phase up to 450,000 is essential tothe present invention. Preferably the molecular weight is in the rangeof 7,500 up to 50,000 or to 450,000. It has been found that excellentpolyvinyl halide processing modifiers result from compositions where themolecular weight of the first stage is of this critical range. Numeroustechniques are known for control of molecular weight and there is nocriticality in the present invention in any particular technique howevera preferred technique is the use of a chain transfer agent such as analkyl mercaptan in the polymerization mix of the first stage or stagesin which the elastomeric phase is polymerized.

Suitable chain transfer agents in this invention include the C to C andhigher alkyl mercaptans particularly n-dodecyl mercaptan. Othertechniques for controlling molecular weight of the elastomeric phaseinclude the use of peroxide, operations at high temperatures of the useof allyl compounds.

The polymerization reactions can be initiated by either thermal or redoxtype initiator systems. Examples of thermal initiators include theorganic peroxides, such as benzoyl peroxide, substituted benzoylperoxides, acetyl peroxides, lauroyl peroxide, t-butyl hydroperoxide,di-t-butyl hydroperoxide, peresters, such as t-butyl peroxypivilate,azo-type initiators such as azobisisobutyronitrile, persulfates, suchassodiurn, potassium or ammonium persulfate, and peroxyphosphates suchas sodium, potassium, or ammonium peroxyphosphate. Redox initiators aregenerally a combination of a hydroperoxide, such as hydrogen peroxide,t-butylhydroperoxide, cumene hydroperoxide, di-isopropylbenzenehydroperoxide, and the like, with a reducing agent, such as a sodium,potassium, or ammonium bisulfite, metabisulfite, or hydrosulfite, sulfurdioxide, hydrazine,'ferrous salts, ascorbic acid, sodium formaldehydesulfoxylate and the like, as are well known in the art.

Examples of emulsifiers or soaps suited to polymerization processes ofthe present invention include alkali metal and ammonium salts of alkyl,aryl, alkaryl, and aralkyl sulfonates, sulfates and polyether sulfates,etl'ioxylated fatty acids, esters, alcohols, amines, amides, alkylphenols, complex organophosphoric acids and their alkali metal andammonium salts.

The thermoplastic vinyl halide polymers utilized in the presentinvention are the polymers and copolymers of vinyl halides, preferablychlorides, widely utilized in the production of plastic articles, Thesepolymers are referred to'as vinyl halide or vinyl chloride polymers inthe present invention, and for most all uses must be modified,compounded or copolymerized with other materials to provide processableand useful compositions. For the purpose and scope of this specificationthe term vinyl chloride polymers or compositions will include allcompositions which have vinyl chloride or other halide as the major(greater than 50%) component monomer. The compositions include but arenot limited to: poly(vinyl chloride) [PVC], copolymers of vinyl chloridewith other monomers that include vinyl molecular weight distribution ofthe polymers is notcritical to the aims, purposes and results of usingthis invention. For general applications vinyl chloride polymers withFikentscherK-values in the range of 40 to 95', preferably about 50 to75, are generally used. The

F ikentscher K-value is determined by the formula 16 where C is 0.5gm/lOO ml. concentration of polymer in solvent,

[v] rel is relative viscosity in cyclohexanone at 25C. and I K isFikentschervalue.

When copolymers of vinyl chloride are utilized in the' practice ofthepresent invention, it is usually preferable tofutilize a polymercontaining from 0 to weight percent of comonomer. The preferredcomonomer is preferably the vinyl alkanoate, and is most preferablyvinyl acetate. The most preferable copolymer' contains up to 10 weightpercent of the comonomer, with the remainder being vinyl chloride.

The copolymers of vinyl chloride and another monomer, mentioned above,are often softer than homopolymers of vinyl chloride.

Finally, the most preferred polymer, and the polymer which is mosteffectively modifiedby the composite interpolymers of the presentinvention is the homopolymer of vinyl chloride. I

The above copolymers vary in physical characteristics such as viscosity,and molecular weight. The copolymers generally are of slightly lowermolecular weights than PVC. Also, the viscosity values are oftenslightly lower, although generally within the above range. Thesedifferences however, are not limiting to conventional lubricants, vinylhalide polymers containing the modifiers of the present invention maybeused without any of these other conventional lubricants. In

some instances however it may be advantageous to uti-' lize thecompositions ofthe present invention with lubricants. In such casessuitable lubricants include stearic acid, stearyl alcohol, licosanol,and other known types. Certain known lubricants may impart improvedprocessability to polyvinyl halides at high temperatures the presentinvention which is directed to modifying such copolymers and not thepolymers themselves. The polymers, however, as is obvious, must besuitable for the use desired when modified, and physically must be of atype to which the present modifiers can be added. Blends of thecomposite interpolymer and the vvinyl halide polymer can be accomplishedby any convenient technique. Entirely satisfactory blends can beaccomplished on a roll mill at convenient and customary operatingconditions, such as about 350F. in about 5 minutes or less time. Drymixing techniques, as with a mechanical mixer-blender device, can alsobe employed. The powder blends can, if desired,'be'processed incommercial extrusion equipment at conditions varying with the molecularweight of the polyvinyl halide used and the equipment employed for thatpurpose.

Certain processing aids, stabilizers, and the like are oftenincorporated in the blades. The stabilizers which serve to prevent thebreakdown of the polyvinyl halide,

but these lubricants adversely affect clarity of the polymers. Thispoint will be illustrated in the examples of this specification by acompa'rison between compositions containing a conventional lubricant andcompositions containing the acrylic composite interpolymer of thisinvention.

xOther inclusions of the blends prepared in accordance withthe presentinvention include colorants, includingorganic dyes, such asanthraquinone red, and the like, organic pigments and lakes such asphthalocyanine blue and the like, and inorganic pigments such astitanium dioxide, cadmium sulfide, and the like; fillers and particulateextenders such as carbon black, amorphous silica, asbestos, glassfibers, magnesium carbonate, and-the-like; plasticizers such as dioctylphthalate, dibenzyl phthalate, butyl benzyl phthalate, hydrocarbon oils,and the like; and impact modifiers such as typicalmethacrylate/butadiene/styrene modifiers and others.

- While only a few of such materials have been specifically recited, itis not intended to exclude others; the recitation is exemplary only, andeach category of additives is common and well-known in the art,including extremely large numbers of materials which are equally .wellsuited for inclusion in the materials of the present invention.

Such inclusions can be made at any stage of preparation in accordancewith accepted techniques wellknown to those ordinarily skilled in theart, in proportions which are commonly employed. Such additionalmaterials are not of particular significance in the present inventionand form no part thereof.

To assist those skilled in the art in the practice of the presentinvention, the following modes of operation are set forth asillustrations, parts and percentages mean by weight unless otherwisespecifically noted;

EXAMPLE I The following procedure illustrates a process for making themultiphase acrylic composite polymers'of the present invention. Thepolymer illustrated is characterized by a butyl acrylate/styrene (40/60)first stage and a methyl methacrylate/ethyl acrylate (45/5) secondstagevalue where this ratio of the first stage to the second stage is1/1.

Two parts of acetic acid (5% aqueous solution) and 881 parts ofdistilled water are mixed under nitrogen with stirring. The temperatureis adjusted to 40C. and 82 parts of amonomer mixture is added-Themonomer mixture contains 5 parts acetic acid (5% aqueous solution), 3.5parts of a 20% aqueous solution of sodium lauryl sulfate, 1.5 parts ofan 80% concentrate of the primary phosphates ofoctylphenoxypolyethoxyethanol in water, 17-0 parts of distilled water,15 parts ndodecyl mercaptan, 200 parts n-butyl acrylate, 300

lubricants, is blended at26/20 rpm. for 3 minutes at 350F. The mixtureis then formed into sheet by milling, 3 minutes at 425F.. 21/20 rpm. Thesheets are compression molded into At inchthick slabs at 350%.

parts styrene and 5 parts cumene hydroperoxide. A so 5 according to acycle of 3 minute preheat, 2 minutes at lution (26 parts) ofl partsodium sulfoxylate formalde- 70 tons pressure followed y 3 minutescooling under hyde in 25 parts water is added and the nitrogen spargeQFCSSUFB- ring the high temperature milling operais reduced. Over 1.5hours an additional 618 parts of e s p are rated for roll releaseaccording to the above monomer mix are added. After the reaction thefollowmg SYSlBITlI is completed, the product is filtered and theemulsion 1o O 1 (poor) only edges of stock can be 1s evaporated 1n. avacuum oven for 2 to 3 days-at 60 removed with diffi l C. to give aseml-solld material, [u]aCctne 0.1 l. P the stock Distilled water, 484parts and 796 parts of an emul- 6 (good) most f h Stock can be removedsion of the preceding-prepared polymer (250 parts t some difficultysolids) are mixed under nitrogen sparge. The tempera- E (excellent) be iture'is adjusted to 44 45C. and asolution (26 parts) of l part sodiumsulfoxylate formaldehyde in 25 parts These samples are also rated formill stability and clarwater is added. A monomer mixture, 359.63 parts,is ity of final sheet according to standard tests.

Table I Mill Intrinsic Roll Stability Clarity Viscosity Release Min.Color Per- Perin At 1 At 3 to at cent cent Composition Acetone Min MinColor 3 Min. WL llaze Unmodified Polyvinyl Chloride F P- 1% yellow 80.011.2 A 0.78 E+ 1% yellow 79.5 14.2 B 0.11 13+ 13+ 1 /1 yellow 80.2 13.2C F+ P+ 1% yellow 70.0 15.0 D 0.83 E+ E+ 1% yellow 79.0 12.3 D 0.87 12+15+ 11/2 yellow 80.5 11.8 o 1.0 13+ 15+ 192 yellow 81.2 15.1 D 0.84 E+12+ 1% yellow 70.0 18.9 D 0.91 13+ E 1% yellow 78.4 9.9 D 1.0 E G- 1%yellow 78.0 15.1 v D 1.3 (3+ G 1% yellow 70.8 12.9 D 1.3 G- G- 1 /4yellow 82.2 8.2 D 1.7 F+ F+ 1% yellow 80.0' 11.2

then added to the reaction mixture over a period of Composition Acontains the modifier prepared in Exabout one hour. The mixture,contains 1.25 parts of an ample l, B contains a low molecular weight 80%concentrate of the primary phosphate ofoctyl- 40 (M,.-14,000) polybutylacrylate/N-vinyl pyrrolidine; phenoxypolyethoxyethanol in water, 108parts of dis 95/5, C contains a styrene/butyl acrylate; 60/40 cotilledwater, 225 parts methyl methacrylate, parts polymer modifier, and Dcontains astyrene/butyl acryethyl acrylate and 0.38 parts cumenehydroperoxide. late first stage/Imethyl methacrylate second stage; Theresulting product (butyl acrylate/styrenel/methyl /20l/50.methacrylate/ethyl acrylate20/30l/45/5) is cooled and filtered throughcheesecloth. An aliquot of the emul- EXAMPLE 51011 is p l' in a Yacuumfor'z t0 3 y at Various modified polyvinyl chloride compositions [0 vy asolld of j The are prepared by milling 100 grams of mixtures ofmodibalance of the emulsion Was p y dlled Wlth g fier and polyvinylchloride for 5 minutes at 425F., recovery and good product to dustingratio. 21/20 rpm roll sheets followed by compression molding into 18inch thick slabs at 350F. according to a cycle EXAMPLE H of a 3-minutepreheat; 2 minutes compression at 70 ton The composition prepared inExample land other pressure followed by 3 minutes cooling underpressure. polymers indicated in Table l are prepared according Table IIshows processing results and clarity determinato the same generalprocedure and incorporated into polyvinyl halide compositions by thefollowing procedure.

One hundred grams of ahand mixture of 97 parts of a polyvinyl chloride,3 parts of the modifier indicated in the Table l, 2 parts of a tinstabilizer, and 1.0 parts tions for the various modified compositionsindicated. Composition A contains a 30 parts styrene/20 parts butylacrylate first stage and a 50 parts methyl methacrylate second stagepolymeric motfiier, composition B contains a low molecular weight (M,.l4,000) polybutyl acrylate, C contains a styrene/butyl acrylate;

Table [1 Processing H (lllrity Intrinsic Flex Percent Viscosity TimeRolling Hot White Light Percent Composition ln Acetone (Minutes) BankStrength Thermoplasticity Release Transmission Haze Unmodified PolyvinylChloride 2 F F F G 86.4 5.7 A 0.83 2 (1+ (3+ 0 E 84.0 (1.0 A 0.87 2 0+6+ 0+ E 87.0 6.9

12 TABLE II Continued 1 Processing Clarity Intrinsic Flex Percent IViscosity Time Rolling Hot White Light Percent Composition In Acetone(Minutes) Bank Strength Thermoplasticity Release Transmission Haze A 1.02 G+ G+ G E 87.5 4.9 A 0.84 2 (1+ (3+ G+ E 86.0 7.6 A 0.91 1% (3+ 0+ (1+E- 89.0 5.1 A 1.0 1 /2 0+ (3+ G E- 87.5 6.5 A 1.3 1 /2 (1+ (1+ G E- g83.0 10.6 A 1.3 .1'/z (1+ (1+ 0+ E- 84.6 9.0 A 1.7 l'/z 0+ 0+ G+ E- 86.25.8 B 1V: 0 G F+ E+ 84.5 5.9 C 0.11 3 F+ F+ F+ E+ 85.0 9.4 D 0.96 2 0+ GG E+ 87.0 5.7

60/40 copolymer modifier and D contains a 30 parts styrene/ parts butylacrylate firststage and a 45 parts methyl methacrylate/S parts ethylacrylate second stage polymeric modifier. prepared in accordance withthe procedure of Example 1 except that where necessary to controlmolecular weight, a small percentage of n-dodecylmercaptan is addedtothe first stage monomer mixture.

lar weight on processing and compositional properties. 15 EXAMPLE IV Inthis example, the polymers shown in Table III are prepared in accordancewith the procedure of Example I. The polymers'are then incorporated.into polyvinyl 2O chloride compositions by the procedure of Example 11and are tested for roll release I and mill stability at 425F. and 380F.with the'results as shown in Tables Compositions A and D are' Thisexample illustrates the effect of varying molecu- IV and V.

Table [II intrinsic Intrinsic 1 Ration of Viscosity Viscosity FirstFinal First Stage/ ln Acetone ln Acetone Stage Stage Final Stage FirstStage. for Polymer A styrene/ methyl hutyl methacrylate/ acrylate; ethylacrylate, /20 /5 /50 0.11 0.96 B styrene/ methyl butyl methacrylate/acrylate; cthyl acrylate. 36/24 36/4 /40 0.13 0.91 C styrene/ methylbutyl methacrylatel acrylate; ethyl acrylate 42/28 27/3 /30 0.12 0.53

Table IV Percent of Roll Release Minutes Color Total Poly-vinyl I At 1At 3 to at 3 Composition Chloride Composition Minute Minutes ColorMinutes Unmodified Polyvinyl Chloride P P 1 orange A 1 E G 1% yellow A 26+ G 1% yellow A 3 E- E 1% yellow B 1 'E G+ 1% yellow B 2 E E+ 1 /4yellow B 3 E: E+ 1% yellow .C 1 E- E 1% yellow C 2 E- E+ 1% yellow Cv 3E- E+ 1% yellow Table V Percent Static Heat Percent of Processing WhiteStability. 380C. Polyvinyl Flex a Light Minutes Minutes Chloride TimeRolling Hot Th'ermo- Tran's- Percent to to Composition Composition'(Minutes) Bank Strength plasticity Release mission Haze Color CharUnmodified Polyvinyl Chloride v 1%- h F F F G 75.8 16.2 10 A 1 54;- A F+F+ F+ G 81.1 10.6" 20 A 3 /4- k F+ G- G- G 79.0 12.7 20-30 90 A 5 A- AF+ G G G 81.1 13.1 20-30 90 B l 34- A F+ v F+ F+ G 79.6 12.6 10-20 90 B3 A F+ G- G- G 80.5 l3.1 20-30 90 B 5 A- A F+ .G G G 84.1 7.3 20-30 90 C1 /4- V: F+v F+ F G 83.5 8.4 10-20 90 C 3 A- A F+ F+ F+ G 81.6 9.6 20-3090 C 5 A- V2 F+ F+ F G 80.6 10.0 90

EXAMPLE v In this example a multiphase acrylic composite polymer of thecomposition; first stage, 50 parts butyl acrylate; final stage, 45 partsmethyl methacrylate/ parts ethyl acrylate, is prepared in accordancewith the procedure of Example I. The polymer is then incorporated into apolyvinyl chloride composition by the procedure of Example [I and istested for roll lease and mill stabilstyrene/butyl acrylate (n-dodecylmercaptan)//second stage: methyl methacrylate/ethyl acrylate; 36/24(3%)l/36/4. The composition contains 97 parts polyvinyl halide, 3 partsof the modifier; 2.0 parts of a tin stabilizer 0.8 parts of a glycerolmonostearate internal lubricant and 0.2 parts of a fatty acid esterlubricant. Composition B contains 100 parts polyvinyl chloride, 2 partsof the tin stabilizer, 1 part of a low molecular weight polyethylenelubricant and 0.8 parts of the glycity at 425F. with the results asshown in Table VI. erol monostearate internal lubricant and 0.2 parts ofTable VI Roll Release Heat Stability Clarity Percent At Relative PercentModifier in l 6- 2 At 5 Minutes Stability at White Light PercentComposition Polyvinyl Chloride Minutes Minutes to Color 5 MinutesTransmission Haze Unmodified Polyvinyl Chloride P P if: P 80.0 8.8 butylacrylatel/ methyl methacrylate/ ethyl acrylate (50//45/S) 5 6+ (3+ l 'h-2 G- 29.6 93.2

3 G+ G l 'h- 2 G-- 45.5 58.7

EXAMPLE VI As pointed out above in the specification the processabilityof polyvinyl halide compositions can be improved with conventionallubricants at the expense of clarity. The following example illustratesthe foregoing, comparing a conventional lubricant with a composition ofthe present invention. Table VII shows polyvinyl halide compositionscontaining the respective lubricants or modifier. In each instance, rollrelease is determined after 3 minutes milling at 425F., 21/20 rpm.Clarity is the fatty acid ester lubricant. Composition C contains 100parts polyvinyl chloride, 2 parts of the tin stabilizer, 0.8 parts ofthe glycerol monostearate internal lubricant and 1.5 parts of the fattyacid ester lubricant. The unmodified composition contains 100 partspolyvinyl chloride, 2 parts of the tin stabilizer, 0.8 parts of theglycerol monostearate internal lubricant and 0.2 parts of the fatty acidester lubricant.

. determined after 7 minutes milling at 350F., 26/20 rpm and compressionmolding into As inch thick sheets. EXAMPLE V Composition A is polyvinylchloride modified with the modifier-first stage.

Table V In this example, stocks weighing 100 grams are pre flexed for 3minutes at 350 F., 26/20 rpm, before mill- Clam ing 3 minutes at'425F.,21/20 rpm. Proportions of y R0" Percent white Percent monomers in thepolymer modifier compositions are in Composition Release LightTransmission Haze P Unless lndlcated percentage.

Unmodified lgilllyo rliflil P 87 5 6 9 This example shows that themultiphase acrylic com- A E posite polymers of composition otherwiseaccording to g the present invention, but with a crosslinked first stage50 are not suitable in the present invention.

Table VIII Mill Stability Roll Release Minutes Color at Composition ofModifier At l Minute At 3 Minutes to Color 3 Minutes Clarity First StageFinal Stage Styrene/butylmethyl methacrylate (nacrylate/ethyldodecylmer' acrylate; 36/4 E- E l% yellow clear captan);

36/24 (3%) butylacrylate methyl meth- (n-dodecylacrylate/ethylmercaptan); acrylate /5 E E+ W; yellow opaque (3%) butylmethmethyl methacrylate (tacrylate/ethyldodecyl meracrylate captan) 45/5G+ G I'A yellow opaque Table Vlll Continued Mill Stability Roll ReleaseMinutes Color at Composition of Modifier At l Minute At 3 Minutes toColor 3 Minutes Clarity butylacrylate/ methyl meth butylene diacry- Yacrylate a late; 49.5/0.5 F+ P+ 1% yellow opaque Unmodified Polyvinyl vChloride P P clear What is claimed is: l

1. A multiphase acrylic composite polymer comprising 50 to 90 weightpercent (A) a first non-crosslinked phase of viscosity average molecularweight of about 7,500 to 50,000 polymerized from a first monomeremulsion of at least 25 weight percent of at least one alkyl acrylatewherein said alkyl group has I tol8 carbon atoms, to 75 weight percentof another acrylic monomer and 0 to 75 percent of anothercopolymerizable ethylenically unsaturated monomer; and 10 to 50 weightpercent (B) a final, rigid thermoplastic phase polymerized in thepresence of said first phase from an emulsion of about 35 to 100 weightpercent of at least one monomer which is methacrylate, acrylate, styreneor substituted styrene, 0 to 65 weight percent of anothercopolymerizable ethylenically unsaturated monomer; wherein the-rigidthermoplastic phase has a viscosity average molecular weight of fromabout 4 X 10 to 5 X i I 2. The polymer of claim 1 in which said firstphase 1 yellow (A) is polymerized from a monomer emulsion of to 95weight percent of the alkyl acrylate, 3 5 to 65 weight percent of theother acrylic monomer and to 65 percent of another copolymerizableethylenically unsaturated monomer. v v

3. The polymer of claim l'in which said rigid thermoplastic phase ispolymerized from an emulsion of 50 to 90 weight percent of at leastone'monomer which is a methacrylate, acrylate, styrene or substitutedstyrene,

5' to 15 weight percent of another acrylic monomer and 5 to 15 weightpercent of another copolymerizable eth-

1. A MULTIPHASE ACRYLIC COMPOSITE POLYMER COMPRISING 50 TO 90 WEIGHTPERCENT (A) A FIRST NON-CROSSLINKED PHASE OF VISCOSITY AVERAGE MOLECULARWEIGHT OF ABOUT 7,500 TO 50,000 POLYMERIZED FROM A FIRST MONOMEREMULSION OF AT LEAST 25 WEIGHT PERCENT OF AT LEAST ONE ALKYL ACRYLATEWHEREIN SAID ALKYL GROUP HAS 1 TO 18 CARBON ATOMS, 0 TO 75 WEIGHTPERCENT OF ANOTHER ACRYLIC MONOMER AND 0 TO 75 PERCENT OF ANOTHERCOPOLYMERIZED ETHYLENICALLY UNSATURATED MONOMER; AND 10 TO 50 WEIGHTPERCENT (B) A FINAL, RIGID THERMOPLASTIC PHASE POLYMERIZED IN THEPRESENCE OF SAID FIRST PHASE FROM AN EMULSION OF ABOUT 35 TO 100 WEIGHTPERCENT OF AT LEAST OE MON0MER WHICH IS METHACRYLATE, ACRYLATE, STYRENEOR SUBSTITUTED STYRENE, 0 TO 65 WEIGHT PERCENT OF ANOTHERCOPOLYMERIZABLE ETHYLENICALLY UNSATURATED MONOMER; WHEREIN THE RIGIDTHERMOPLASTIC PHASE HAS A VISCOSITY AVERAGE MOLECULAR WEIGHT OF FROMABOUT 4 X 10**5 TO 5 X 10**6.
 2. The polymer of claim 1 in which saidfirst phase (A) is polymerized from a monomer emulsion of 25 to 95weight percent of the alkyl acrylate, 35 to 65 weight perceNt of theother acrylic monomer and 35 to 65 percent of another copolymerizableethylenically unsaturated monomer.
 3. The polymer of claim 1 in whichsaid rigid thermoplastic phase is polymerized from an emulsion of 50 to90 weight percent of at least one monomer which is a methacrylate,acrylate, styrene or substituted styrene, 5 to 15 weight percent ofanother acrylic monomer and 5 to 15 weight percent of anothercopolymerizable ethylenically unsaturated monomer.
 4. The polymer ofclaim 1 in which the rigid thermoplastic phase is characterized by aviscosity average molecular weight of from 750,000 to 1 X
 106. 5. Thepolymer of claim 1 comprising 50 to 70 weight percent of the first phaseand 30 to 50 weight percent of the second phase.